Effects of airborne emissions from a natural gas processing plant on the production of swine

Specific-pathogen-free swine were produced under field conditions in a high emission exposure area and a low emission exposure area of a natural gas processing plant over a period of 38 mo. Production parameters were measured and respiratory tissues sampled. Sulfur dioxide concentration was monitored in the high exposure area. Average concentrations of SO₂ exceeded 0.20 ppm for 30 min on 23 occasions during one of four rate of gain and feed conversion trials. Average concentrations of SO₂ exceeded 0.02 ppm for 24 hr on 5 days when farrowings occurred. No significant difference was found in rate of gain, feed conversion, piglets born per litter or piglet survival, between swine produced in the two areas. No histological a alterations such as loss of cilia, atrophy of goblet cells or cellular metaplasia were observed in any respiratory epithelia from 62 pigs.